mitchell



(No Model.) 2 SheetsSheet 1.

M. L. M'ITGHELL.

BUFFER FOR GAS CDMPRESSOR VALVES Np. 35659? Patented Jan. 25, 1887.

By A Home 2 Sheets-Sheet 2.

(No Model.)

M. L. MITCHELL.

BUFFER FOR GAS COMPRESSOR VALVES.

Patented. (fan. 25, 1887..

WITNESSES NHED Smarts r rricn.

MARCUS L. MITCHELL, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE DE Ll; VERGXE REFRIGER-ATING MACHINE COMPANY, OF NEXV YORK, N. Y.

BUFFER FOR GAS-COMPRESSOR VALVES.

SPECIPICATIONforming part ofLetteIs PatentNo. 356,597, dated January 25, 1887. Application filed October 522, 18 B5. Serial No. l80,618. (No model.)

To all whom it may concern:

Be it known that 1, ounces L. llIITCHELL, of the city of St.Louis,in the State of Missouri, haveinvcnted certain new and useful Improve- 4 meats in Bnfiers for Gas-Compressor Valves, of which the following is such a full, clear, concise, and exact description as will enable others skilled in the art to which my invention appertains to make and use the same, referonce being had to the accompanying drawings, forming part of this specification.

My invention relates more especially to gascomprcssors for rcfrigeratirig-machines which.

use a cooling, sealing, and lubricating liquid,

[5 forming what is known also as a liquid piston, and may be adapted to both vertical and horizontal compressors used in such machines, and also to use in connection with. gas-compressors for other than'rcfrigerating purposes.

In some vertical gascompressi-ng cylinders heretoforecoustructcd the discharge-valvehas been made to lift up into a dome or valve- .chamber located above the compressor-cylinder, and intp which dome or chamber the 2' compressed gas is discharged by the lifting of this valve during the upward or compression stroke of the compressor-piston. oil thus discharged into the dome or valvechamber of the compressor is conducted therefrom by a discharge-pipe communicating therewith, and leadiug to what is termed an oilseparating tauk. The discharge valve in such compressors, which is preferably cupshaped, made of metal, and of necessity ,very

5 large, is also very heavy. If the height to which this valve may be raised or lifted in the dome of the compressor is notlimited by some mechanical means,the force exerted upon it by the compressed gas entering the dome, being variable, will at times raise the valve much higher than is really necessary to allow a free passage of the compressed gasand'oil, and the weight of the valve would cause it to de-. sceud with considerable force, and oftentimes before the end of the discharge-period, in

which case it would strike the valve-seat at or time whensdch seat was not flooded by or sub merged in oil, and thus an injury to either the valve or thevalve-seat'would inevitably 5o ensue. In some gas-compressors for'refrigcratingwmachines the discharge-valve hasbeen Thegas and responding parts.

made to work in ways or guides, and the lift of the valve has been limited by projections or stops on such guides; and in some instances the projections for limiting the upward move.- ment of the valve have been made to extend all around the dome or valve-chamber. It

was found, however, that when these projections or stops were located low enough to form a sufficiently-small passage for the compressed gas and oil as that its flow into the valve-chain her or dome would be retarded to the extent requisite to cause it to exert the necessary pressure upon the valve to hold it against such projections or stops and keep it from re- 6 seating during the discharge-period, the upper edges of the discharge-valve cup soon become burrcd by being constantly knocked against the stops. In consequence of this continual hammering some porti ns of the valve would become larger in diameter, and it would eventually refuse to reseat after being lifted by the discharged. gas; and not only so,

the valve would sometimes break, thus causing delay and annoyance, and not infrequently 7 5 serious losses to the owner of the machine,who depended upon its continuous and perfect working. Aside from this, the great and disagreeable noise which in such construction was occasioned when the machine was running at a high speedsay fifty or sixty revolutions per minutewasa1so aserious objcction,and, moreover, there was danger of breaking thevalve or guide-stops by running the machine to its otherwise full capacity, and it was therefore neccssary,iu order to insure safety, that the machine should be run at a moderate speed, which of course lessened its daily performance.

To avoid theseobj actions and to prevent the delays and losses already mentioned, as well as to increase the working capacity of the machine, is the object of my invention, which consists in providing a holder to receive the valve when lifted or forced upward without barring orbreaking it, andin addition thereto 5 in providing a cushion which will render noiseless the movement of the valve against the buffer. i y I In the drawings similarletters represent cor- Figure 1 is a central vertical section of a,

singleacting gas-con1prcssor and dome or the butter-head is the dome or is created below it,

valve-chamber, such as is usedin some refrigerating machines which circulate a cooling,

sealing, and lubricating liquid, and showing also a buffer secured within the dome above the discharge-valve, 'which is provided with-a recess or depression corresponding to the head of the butter. Fig. 2 is a central vertical section through the dome, discharge-valve, dia- ,phragm-plate', and upper part of the compressor-cylinder on a largerscale. In this figshown as corresponding to the valve-cup, hut-the recess in the bottom plate is omitted, the outlets in the upwardly-projecting walls forming the valvecnp being located suflicient'ly high to cause the valve to retain a portion of the oil,which forms a cushion for the butter. Fig. 3 is a like view, but shows the bufl'eras seemed within the dome, and also a recessin the bottom plate of the discharge-valve. This figure also shows the under side of the buffer-head concave, and shows the edges of the responding to the beveled edges of the recess in the bottom plate of the valve. I

A represents the dome or dischargevalve chamber; B, the butter, the underside of which is preferably concave, while (3 represents the diaphragm-plate with the valveseatc, and E the outlet from the dome for the gas and oil; From this outlet thegas and oil may passinto an oil-separating tank, (not sh5wn,) which in refrigerating-machines is generally interposed between the compressor and a gas-condenser, the latter not appearing in the drawings. In this tank, to which the gas and oil flow from valve-chamber, the oil is separated from the hot con-ipresscd gas.

In all the figures M represents the cup shaped discharge-valve, and in Figs. 1 and 3 m the'proiectiug walls surrounding a. receptacle for oil, which -I sometimes make within the base or bottom plate of the discharge-valve, and which is prelcrably but slightly. larger than the head of the butter 13, but corresponding to it in shape as near as may be, and into which oil-receptacle t-hehead of the buffer enters when the discharge-valve is lifted.

In each figure m m represent openings in the upwardly-projecting walls forming the cup of the discharge-valve, for alternately admit;-

ting oil to and discharging it from the cup of.

the valve M. v I

In Fig. 1 F represents the compressor-piston;f, the piston-val.ve, andf the piston-rod; G, the suction-nozzle or gas-inlet,- y, the suction-valve, and H the oil-inlet. v

The piston F is actuated in the usual way, and when it moves upw'arda partial vacuum and as the suction-valveg lifts the gas fills the compressor. "pon the downward stroke of the piston a partial vacuum is created above it, the lifts and the suetion-valve g closes, and the gas-passes through the openings in the piston between the ribs 4 ii. to the upper or compression chamber of the compressor. Duringthis period a. certain quantity of oilunder a presshead beveled and corpiston-valve f 1 during or after the suctionstroke ure above the pressure of the gas entering the compressor is injected into the compressor through the oil-inlet H, either by means of a pump or other device. The piston F, near the end ot'its downward stroke, dips into the oil I in the bottom of the compressor, and a tity of oil equal to the quantity injected durb the downward stroke of the piston also passes through theopcnings in the piston. Upon the return or upward stroke of the piston F the gas contained in the compressionchamber of the compressor will be compressed to a pressure a. little above the pressure 'ohtaining in the dome or discharge-valve chamher A, when the dischargevalve M will lift. I and be forced against the buffer B, the head of which enters the valve-cup, as shown in Fig. 2, and when the valve M has the recess formed by the walls at shown in Figs. 1 and 3) the {head of the bufi'er enters such recess. The rapid passage of the compressed gas through vent the valve M from descending until the moment when the oil which is lying above the piston is being forced through the valve-passage, and the valve will fall upon the oil,whicli floods the lower portion of the dome A, thus suhmerging the valve-scat, the seating of the valve will oil new contained in the openings or into up to the lower edge the recess formed by he noiseless. The

the valve and fills its cup of such openings, and if the walls at be present in the bottom plate of the valve M this recess will also be filled with oil. TWhen the valve M is again lifted toward the bufier B,the head of the buficr will be met by the oil contained in the valve-cu p, which it; must displace before the valve can strike it, and i f a recessbe formed in the bottom plate of the valve the hun erhead must also displace the oil contained therein. In either case the valve will be so cushioned by the oii as that the seating thereof will be noiseless.

By constructing the discharge-valve so that it will receive and retain a portion of the oil admitted by it to the. dome or chamber such oil willalways be present when the machine is in operation, and thus a. cushion will be presented to the buffer-head before the valve strikes against it, and by means of such enshion 1 am not only enabled to 'avoid the noise occasioned by the use of large discharge-valves constructed as heretofore,

0 Inc can consequently perform a greater amount of work within a given time, because of the fact that it can be run at a much higher rate of speed. My invention maybe applied to single or double acting compressors using a liquid base,

and the oil may be injected into the lower or upper chamber of the compressor,

of the piston or during or before thecompression-stroke. It may also beapplied to horizontal compress ors, provided the valves of i such compressionquan the aperture in the diaphragm-plate will preand consequently the dome flows through but all liability of reaking the parts is obviated, and the maand either 1 0 d 5 in practice I prefer to nse'metalliccup-shaped 1o 'usin acoolin gsealiu andlubricatin li aid" in such dome or chamber with a discharge- 20 valve adapted to move toward the said buffer,

.25 substantially as described.

cylinders lift vertically or at right angles to the center line of such compressors.

I may employ diiferently-shaped bufi'ers, valves, and domes from those described, but

valves, bell-shaped domes and hu'fi'e'ra'fas shown. The lift of the valve inay be made adjustable; but having determined the proper lift of valves of every size in compressors I prefer to have the bnfier stationary, and thus prevent the use of. unnecessary or moving parts in the dome. 4

, Having thus described my invention, hen;

Patent, is-

'1. In a gas-compressor having a dome or chamber, the combination of a buffer secured such valve having a recess or depression therein corresponding substantially to the buffer-head. and adapted to receive such hufi'er' head when the valve moves up to the same,

2. In a gas-compressor having a donie or valvechamber,

the combination of 'a bufl'er located within such dome or chamber with a discharge-valve adapted to hold and retain a portion of the liquid admitted by it to the chamber and to present the retained liquid to the head of the bnifer, whereby the valve is prevented from coming inscontact with the 'buficr-head until it has displaced the liquid retained by the valve, substantiallyas andfor the purpose set forth.

'3. In a gas-confprcssornsing a cooling,seaT- ing, and lubricating liquid, the combination of a bulfer secured within the dischargevalve chamber with a cup-shaped discharge-valve having therein an oil-receptacle corresponding substantially to the shape of the bufi'er-head and adapted to hold aliqnid wherebyncnshiou for the bufier may be formed of the liquid contained-in such receptacle or recess, which is thus made to neutralize or render noiseless the concussion occasioned by the forcing of the valve up to the buffer-head, substantially as described.

MARCUS L. MITCHELL.

Witnesses:

WM. A. HAREX, LOUIS KAUFMAN). 

